摘要：The article is focused on increasing the efficiency of fireplace inserts by means of a device used to preheat the combustion air with a part of the heat from the flue gases. The proposed device is a heat pipe with a closed loop, where its evaporator takes heat from the flue gas in front of the chimney orifice and transfers it via saturated steam to the condenser. This heats the combustion air and thus increases the thermal efficiency of a small heat source.
